Piperidine compounds and their use as stabilizers

ABSTRACT

Compounds of formula (I) ##STR1## in which R 1  is hydrogen, O°, CN, NO, cyanomethyl, C 1  -C 12  -alkyl, C 3  -C 12  -alkenyl or C 3  -C 12  -alkynyl subject to the proviso that the carbon atom attached to the nitrogen atom is a primary carbon atom, C 7  -C 12  -aralkyl, C 1  -C 12  -acyl, 2,3-epoxypropyl, OH-monosubstituted C 2  -C 6  -alkyl or 2,3-dihydroxypropyl, R 2  is hydrogen, C 1  -C 18  -alkyl, C 5  -C 18  -cycloalkyl, C 6  -C 18  -aryl or C 7  -C 18  -aryalkyl, R 3  is C 6  -C 18  -aryl or a group of the formula (II) ##STR2## in which R 1  is as defined above, n is an integer from 1 to 4 and R 4  is an organic or inorganic radical of a valency equal to n are useful for stabilizing organic material against oxidative, thermal and/or light induced degradation.

This is a divisional of application Ser. No. 257,365, filed on Oct. 13,1988, now U.S. Pat. No. 4,927,925, issued on May 22, 1990, which in turnis a divisional of application Ser. No. 008,220, filed on Jan. 29, 1987,now U.S. Pat. No. 4,803,234, issued on Feb. 7, 1989.

The present invention relates to novel piperidine compounds, the usethereof and to the organic material stabilized with the aid of saidcompounds against thermal, oxidative and/or light induced degradation.

It is known that synthetic polymers undergo progressive changes in theirphysical properties, such as loss of mechanical strength and colourchanges, when they are exposed to sunlight or other sources ofultraviolet light. To retard the deleterious effect of sunlight onsynthetic polymers, it has been proposed to use various additives havinglight-stabilizing properties.

FR 2 268 011 describes substituted N,N'-diphenylformamidine compoundsand the use thereof as light stabilizers. JP 85-84258 discloses aprocess for the preparation of substituted N,N'-formamidine derivatives.

The present invention relates to novel piperidine compounds of theformula (I) ##STR3## in which R₁ is hydrogen, O° , CN, NO, cyanomethyl,C₁ -C₁₂ -alkyl, C₃ -C₁₂ -alkenyl or C₃ -C₁₂ -alkynyl subject to theproviso that the carbon atom attached to the nitrogen atom is a primarycarbon atom, C₇ -C₁₂ -aralkyl, C₁ -C₁₂ -acyl, 2,3-epoxypropyl,OH-monosubstituted C₂ -C₆ -alkyl or 2,3-dihydroxypropyl, R₂ is hydrogen,C₁ -C₁₈ -alkyl, C₅ -C₁₈ -cycloalkyl, C₆ -C₁₈ -aryl or C ₇ -C₁₈ -aralkyl,R₃ is C₆ -C₁₈ -aryl or a group of the formula (II) ##STR4## in which R₁is as defined above, n is an integer from 1 to 4 and R₄ is an organic orinorganic radical of a valency equal to n.

If n is 1, R₄ is preferably selected from the group consisting ofhydrogen, CN, --COR₅, --COOR₆, --CO--R₇ --COOR₈, ##STR5## in which R₅ ishydrogen, C₁ -C₁₈ -alkyl, C₅₋ C₁₈ -cycloalkyl, C₂ -C₁₈ -alkenyl, C₆ -C₁₈-aryl, C₇ -C₁₈ -aralkyl or C₁ -C₁₀ -alkyl substituted by C₁ -C₁₈-alkoxy, by C₂ -C₁₈ -dialkylamino or by group of the formula (III)##STR6## where R₁ is as defined above and W is --O-- or ##STR7## whereR₁₅ is hydrogen, C₁ -C₁₈ -alkyl, C₅ -C₁₈ -cycloalkyl, C₃ -C₁₈ -alkenyl,C₆ -C₁₈ -aryl, C₇ -C₁₈ -aralkyl or a group of the formula (II), R₆ is C₁-C₁₈ -alkyl, C₂ -C₆ -alkyl substituted by OH, by C₁ -C₁₈ -alkoxy or byC₂ -C₁₈ -dialkylamino, C₅ -C₁₈ -cycloalkyl, C₃ -C₁₈ -alkenyl, C₆ -C₁₈-aryl, C₇ -C₁₈ -aralkyl or a group of the formula (II), R₇ is a directbond, C₁ -C₁₈ -alkylene, C₂ -C₂₀ -alkylidene, C₇ -C₂₀ -aralykylidene, C₆-C₁₀ -cycloalkylene, C₂ -C₁₈ -alkenylene or C₆ -C₁₀ -arylene, R₈ is asdefined for R₆ or is hydrogen or an alkali metal, R₉ and R₁₀, which areidentical or different, are as defined for R₁₅, or R₉ and R₁₀, togetherwith the nitrogen atom to which they are bonded, form part of a5-membered to 7-membered heterocyclic ring, R₁₁ is C₁ -C₁₂ -alkyl or C₆-C₁₂ -aryl, r is 0 or 1, R₁₂ is C₁ -C₁₂ -alkyl or a group of the formula(II), or the two groups R₁₂ together are C₂ -C₁₂ -alkylene or C₆ -C₂₈-arylene and together with the phosphorus atom and the two oxygen atomsform a 5-membered to 7-membered ring, R₁₃ and R₁₄, which can beidentical or different, are as defined for R₆ or are hydrogen, and X andY, which can be identical or different, are a direct bond, --O-- or##STR8## where R₁₆ is as defined for R₁₅ or is OH-monosubstituted C₂ -C₆-alkyl, or the groups R₁₃ X-- and R₁₄ Y--, which can be identical ordifferent, are a 5-membered to 7-membered heterocyclic group.

If n is 2, R₄ is preferably selected from the group consisting of--CO--, --SO₂ --, --COO--R₁₇ --OOC--, --COCOO--R₁₇ --OOCCO--, --CO--R₁₈--CO--, ##STR9## in which R₁₇ is C₂ -C₁₈ -alkylene, C₄ -C₁₂ -alkylenesubstituted in the chain by 1 or 2 oxygen atoms, C₆ -C₁₈ -cycloalkylene,C₄ -C₈ -alkenylene, C₆ -C₁₈ -arylene, C₈ -C₁₂ -aralkylene or a group ofthe formula (IV) ##STR10## where R₂₃ is hydrogen, C₁ -C₄ -alkyl orphenyl, R₁₈ is a direct bond, C₁ -C₁₈ -alkylene, C₂ -C₂₀ -alkylidene, C₇-C₂₀ -aralkylidene, C₆ -C₁₀ -cycloalkylene, C₆ -C₁₀ -arylene, C₂ -C₁₂-alkylene substituted in the chain by 1 or 2 oxygen atoms or by 1 or 2groups ##STR11## where R₂₄ is as defined for R₁₅, R₁₉ and R₂₁, which canbe identical or different, are as defined for R₁₅, R₂₀ is C₂ -C₁₈-alkylene, C₆ -C₁₈ -cycloalkylene, C₆ -C₁₈ -arylene or C₈ -C₁₂-aralkylene, R₂₂ is as defined for R₁₃ and R₁₄, Z is as defined for Xand Y, or --ZR₂₂ is a 5-membered 7-membered heterocyclic group orhalogen, R₂₅ is C₁ -C₄ -alkyl, s is 0 or 1, R₇ is as defined above andMe is Ba, Ca, Co", Mg, Mn", Ni", Sn" or Zn.

If n is 3, R₄ is preferably selected from the group consisting ofaliphatic C₄ -C₁₈ -triacyl, aliphatic C₆ -C₁₈ -triacyl substituted by anitrogen atom, aromatic or heterocyclic triacyl having up to 18 carbonatoms, substituted aliphatic, aromatic or heterocyclic tricarbamoylhaving up to 24 carbon atoms, a 1,3,5-triazine-2,4,6-triyl group, a.tbd.P group, a .tbd.PO group and a group (--CO--R₇ --COO)₃ Al with R₇as defined above.

If n is 4, R₄ is preferably selected from the group consisting ofaliphatic C₆ -C₁₈ -tetraacyl, aliphatic C₁₀ -C₁₈ -tetraacyl substitutedby two nitrogen atoms, aromatic C₁₀ -C₁₈ -tetraacyl, cycloaliphatic C₁₀-C₂₂ -tetraacyl and a group (--CO--R₇ --COO)₄ Sn^(IV), where R₇ is asdefined above.

R₁, R₁₁ and R₁₂ as C₁ -C₁₂ -alkyl are for example methyl, ethyl, propyl,isopropyl, butyl, isobutyl, t-butyl, pentyl, hexyl, heptyl, octyl,2-ethylhexyl, decyl or dodecyl. C₁ -C₄ -alkyl which may be straightchain or branched is preferred. R¹ as methyl is especially preferred.

R₁ as C₃ -C₁₂ -alkenyl is for example allyl, 2-methallyl, 2-butenyl,2-hexenyl or 10-undecenyl. Allyl is especially preferred.

R₁ as C₃ -C₁₂ -alkynyl may be preferably propargyl.

R₁ as C₇ -C₁₂ -aralkyl is for example benzyl, methylbenzyl,t-butylbenzyl or hydroxybenzyl. C₇ -C₁₀ -phenylalkyl unsubstituted orsubstituted at the phenyl ring by alkyl and/or by OH is preferred.Benzyl and benzyl substituted by C₁ -C₄ -alkyl and/or by OH areespecially preferred.

R₁ as C₁ -C₁₂ -acyl may be an aliphatic or aromatic C₁ -C₁₂ -acyl group.C₁ -C₁₂ -alkanoyl, C₃ -C₁₂ -alkenoyl, C₃ -C₁₂ -alkynoyl, benzoyl andbenzoyl substituted by C₁ -C₄ -alkyl and/or by OH are preferred.Examples are formyl, acetyl, propionyl, butyryl, caproyl, capryloyl,caprinoyl, lauroyl, benzoyl, acryloyl, methacryloyl and crotonyl.

R₁, R₆, R₁₃, R₁₄, R₁₆ and R₂₂ as OH- monosubstituted C₂ -C₆ -alkyl arefor example 2-hydroxyethyl, 2-hydroxypropyl or 3-hydroxypropyl.

R₂, R₅, R₆, R₈, R₉, R₁₀, R₁₃, R₁₄, R₁₅, R₁₆, R₁₉, R₂₁, R₂₂ and R₂₄ as C₁-C₁₈ -alkyl are for example methyl, ethyl, propyl, isopropyl, butyl,isobutyl, 2-butyl, t-butyl, pentyl, isopentyl, hexyl, heptyl, 3-heptyl,octyl, 2-ethylhexyl, nonyl, decyl, undecyl, dodecyl, tridecyl,tetradecyl, pentadecyl, hexadecyl, octadecyl or heptadecyl. R₂ ispreferably C₁ -C₄ -alkyl, in particular methyl.

R₂, R₅, R₆, R₈, R₉, R₁₀, R₁₃, R₁₄, R₁₅, R₁₆, R₁₉, R₂₁, R₂₂ and R₂₄ as C₅-C₁₈ -cycloalkyl are preferably a cycloalkyl group of the formula##STR12## with a being an integer from 4 to 11. Said cycloalkyl groupmay optionally be substituted by C₁ -C₄ -alkyl. Examples arecyclopentyl, cyclohexyl, methylcyclohexyl, dimethylcyclohexyl,trimethylcyclohexyl, t-butylcyclohexyl, cyclooctyl and cyclododecyl.Cyclohexyl unsubstituted or substituted by C₁ -C₄ -alkyl is especiallypreferred.

R₂, R₃, R₅, R₆, R₈, R₉, R₁₀, R₁₃, R₁₄, R₁₅, R₁₆, R₁₉, R₂₁, R₂₂ and R₂₄as C₆ -C₁₈ -aryl are for example phenyl or naphthyl which both may besubstituted or unsubstituted.

R₃ as C₆ -C₁₈ -aryl may be preferably phenyl unsubstituted orsubstituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy, C₂ -C₄ -alkoxycarbonyland/or OH, or may be phenyl substituted by2,2,6,6-tetramethyl-4-piperidyloxycarbonyl or by1,2,2,6,6-pentamethyl-4-piperidyloxycarbonyl. Preferred examples of R₃are phenyl, methylphenyl, dimethylphenyl, trimethylphenyl, ethylphenyl,diethylphenyl, hydroxyphenyl, 3,5-di-t-butyl-4-hydroxyphenyl,methoxyphenyl, ethoxyphenyl, 4-ethoxycarbonylphenyl,4-(2,2,6,6-tetramethyl-4-piperidyloxycarbonyl)phenyl and4-(1,2,2,6,6-pentamethyl-4-piperidyloxycarbonyl)phenyl.

R₂, R₅, R₉, R₁₀, R₁₅, R₁₆, R₁₉, R₂₁ and R₂₄ as C₆ -C₁₈ -aryl may bepreferably phenyl unsubstituted or substituted by C₁ -C₄ -alkyl, C₁ -C₄-alkoxy and/or OH, or may be naphthyl unsubstituted or substituted by C₁-C₄ -alkoxy. Preferred examples of R₂, R₅, R₉, R₁₀, R₁₅, R₁₆, R₁₉, R₂₁and R₂₄ are phenyl, methylphenyl, dimethylphenyl, trimethylphenyl,ethylphenyl, t-butylphenyl, methoxyphenyl, ethoxyphenyl, hydroxyphenyland 3,5-di-t-butyl-4-hydroxyphenyl with phenyl being especiallypreferred.

R₆, R₈, R₁₃, R₁₄ and R₂₂ as C₆ -C₁₈ -aryl may be preferably phenylunsubstituted or substituted by C₁ -C₄ -alkyl and/or alkoxy, or may benaphthyl unsubstituted or substituted by C₁ -C₄ -alkoxy. Preferredexamples of R₆, R₈, R₁₃, R₁₄ and R₂₂ are phenyl, methylphenyl.dimethylphenyl, trimethylphenyl, ethylphenyl, isopropylphenyl,t-butylphenyl, di-t-butylphenyl, 2,6-di-t-butyl-4-methylphenyl,methoxyphenyl and ethoxyphenyl.

R₂, R₅, R₆, R₈, R₉, R₁₀, R₁₃, R₁₄, R₁₅, R₁₆, R₁₉, R₂₁, R₂₂, and R₂₄ asC₇ -C₁₈ -aralkyl may be C₇ -C₁₀ -phenylalkyl unsubstituted orsubstituted at the phenyl ring by C₁ -C₄ -alkyl and/or OH. Examples arebenzyl, methylbenzyl, hydroxybenzyl, 3,5-di-t-butyl-4-hydroxybenzyl and2-(3,5-di-t-butyl-4-hydroxyphenyl)ethyl. Benzyl unsubstituted orsubstituted is preferred.

R₅ as C₂ -C₁₈ -alkenyl is for example vinyl, propenyl, allyl, butenyl,methylallyl, hexenyl, decenyl or heptadecenyl.

R₅ as C₁ -C₁₀ -alkyl which is substituted by C₁ -C₁₈ -alkoxy or C₂ -C₁₈-dialkylamino is for example ethoxymethyl, butoxymethyl, octoxyethyl,2-ethoxyethyl, 3-butoxyethyl, 3-methoxypropyl, 3-butoxypropyl,diethylaminomethyl, dibutylaminomethyl, 2-diethylaminoethyl,2-dibutylaminoethyl or 3-diethylaminopropyl.

R₆, R₈, R₁₃, R₁₄ and R₂₂ as C₂ -C₆ -alkyl which is substituted by C₁-C₁₈ -alkoxy or C₂ -C₁₈ -dialkylamino are for example 2-methoxyethyl,2-ethoxyethyl, 2-butoxyethyl, 2-octoxyethyl, 3-ethoxypropyl,3-butoxypropyl, 4-butoxybutyl, 2-diethylaminoethyl, 2-dibutylaminoethylor 3-dibutylaminopropyl.

R₆, R₈, R₉, R₁₀, R₁₃, R₁₄, R₁₅, R₁₆, R₁₉, R₂₁, R₂₂, and R₂₄ as C₃ -C₁₈-alkenyl are for example allyl, butenyl, methylallyl, hexenyl, decenyl,undecenyl or oleyl.

R₇ and R₁₈ as C₁ -C₁₈ -alkylene are for example methylene, ethylene,propylene, trimethylene, tetramethylene, pentamethylene, hexamethylene,heptamethylene, octamethylene, docamethylene or dodecamethylene. C₁ -C₆-alkylene is preferred. Ethylene is especially preferred.

R₇ and R₁₈ as C₂ -C₂₀ -alkylidene are for example ethylidene,propylidene, butylidene, pentylidene, 4-methylpentylidene, heptylidene,nonylidene, tridecylidene, nonadecylidene, 1-methylethylidene,1-ethylpropylidene or 1-ethylpentylidene.

R₇ and R₁₈ as C₇ -C₂₀ -aralkylidene may be C₇ -C₂₀ -phenylalkylidenesuch as for example benzylidene, 2-phenylethylidene or1-phenyl-2-hexylidene.

R₇ and R₁₈ as C₆ -C₁₀ -cycloalkylene and R₁₇ and R₂₀ as C₆ -C₁₈-cycloalkylene may be a saturated hydrocarbon group with two freevalencies and at least one cyclic unit.

R₇, R₁₇, R₁₈ and R₂₀ are for example cyclohexylene or cyclohexylenesubstituted by C₁ -C₄ -alkyl. Cyclohexylene and methylcyclohexylene arepreferred.

In addition R₁₇ and R₂₀ may be alkylene-cyclohexylene-alkylene with 8 to18 carbon atoms, cyclohexylene-alkylene-cyclohexylene with 13 to 18carbon atoms or alkylidenedicyclohexylene with 14 to 18 carbon atoms.Preferred examples are cyclohexylenedimethylene,methylenedicyclohexylene, isopropylidenedicyclohexylene.

R₇ as C₂ -C₁₈ -alkenylene is for example vinylene, methylvinylene,octenylethylene or dodecenylethylene.

R₇ and R₁₈ as C₆ -C₁₀ -arylene and R₁₇ and R₂₀ as C₆ -C₁₈ -arylene maybe substituted or unsubstituted at the aromatic group. R₇ and R₁₈ arefor example 1,2-phenylene, 1,3-phenylene or 1,4-phenylene. R₁₇ and R₂₀are preferably phenylene unsubstituted or substituted by C₁ -C₄ -alkyl,biphenylene, phenylene-alkylene-phenylene with 13 to 18 carbon atoms,phenylene-alkylidene-phenylene with 14 to 18 carbon atoms, naphthylene.Preferred examples are phenylene, methylphenylene, biphenylene,methylenediphenylene, isopropylidenediphenylene.

If R₉ and R₁₀ together with the nitrogen atom to which they are bondedform part of a 5-membered to 7-membered heterocyclic group, this groupis preferably a saturated heterocyclic group with N and/or O as heteroatoms. Illustrative examples are 1-pyrrolidinyl, 1-piperidyl,4-morpholinyl, 1-hexahydroazepinyl and 4-methyl-1-piperazinyl.

R₁₁ as C₆ -C₁₂ -aryl is for example phenyl or naphthyl which both may besubstituted or unsubstituted. R₁₁ is preferably phenyl unsubstituted orsubstituted by C₁ -C₃ -alkyl and/or C₁ -C₃ -alkoxy. Examples are phenyl,methylphenyl, dimethylphenyl, trimethylphenyl, methoxyphenyl andethoxyphenyl.

If the two groups R₁₂ together are C₂ -C₁₂ -alkylene or C₆ -C₂₈ -aryleneand together with the phosphorus atom and the two oxygen atoms form a5-membered to 7-membered heterocyclic ring, the C₂ -C₁₂ -alkylene groupis preferably a straight chain or branched alkylene group with 2 to 7carbon atoms and the C₆ -C₂₈ -arylene group may be a 1,2-phenylene groupunsubstituted or substituted by C₁ -C₄ -alkyl or may be a biphenylenegroup unsubstituted or substituted by C₁ -C₄ -alkyl. ##STR13##

--XR₁₃, --YR₁₄ and --ZR₂₂ as a 5-membered to 7-membered heterocyclicgroup may be a saturated heterocyclic group with N and/or O as heteroatoms. Illustrative examples are 1-pyrrolidinyl, 1-piperidyl,4-morpholinyl, 1-hexahydroazepinyl and 4-methyl-1-piperazinyl.

--ZR₂₂ may also be halogen, preferably Cl.

R₁₇ and R₂₀ as C₂ -C₁₈ -alkylene are for example ethylene, propylene,trimethylene, tetramethylene, pentamethylene,2,2-dimethyl-1,3-propanedinyl, hexamethylene, octamethylene,decamethylene or dodecamethylene. C₂ -C₆ -alkylene is preferred.

R₁₇ as C₄ -C₁₂ -alkylene which is substituted in the chain by 1 or 2oxygen atoms is for example 3-oxapentane-1,5-diyl or3,6-dioxaoctane-1,8-diyl.

R₁₇ as C₄ -C₈ -alkenylene is for example 2-butene-1,4-diyl.

R₁₇ and R₂₀ as C₈ -C₁₂ -aralkylene are for examplealkylene-phenylene-alkylene with 8 to 12 carbon atoms, preferablydimethylenephenylene (xylylene) which may optionally be substituted byC₁ -C₄ -alkyl.

R₁₈ as C₂ -C₁₂ -alkylene which is substituted in the chain by 1 or 2oxygen atoms is for example 2-oxapropane-1,3-diyl,2,7-dioxaoctane-1,8-diyl or 2,6-dioxa-4,4-dimethyl-1,7-heptanediyl.

R₂₃ and R₂₅ as C₁ -C₄ -alkyl are for example methyl, ethyl, propyl orbutyl.

R₄ as aliphatic C₄ -C₁₈ -triacyl may be C₄ -C₁₈ -alkanetrioylunsubstituted or substituted by OH. Preferred examples are thosetriacyls derived from methanetricarboxylic, 1,1,2-ethanetricarboxylic,1,2,3-propanetricarboxylic, citric or 1,2,3-butanetricarboxylic acids.

R₄ as aliphatic C₆ -C₁₈ -triacyl which is substituted by a nitrogen atomis for example ##STR14##

The group N(CH₂ CO--)₃ is especially preferred.

R₄ as aromatic triacyl having up to 18 carbon atoms is for example atriacyl derived from 1,2,4-benzenetricarboxylic acid or1,3,5-benzenetricarboxylic acid.

R₄ as heterocyclic triacyl having up to 18 carbon atoms is for example##STR15##

A heterocyclic triacyl group with 9 to 12 carbon atoms is preferred.

R₄ as substituted aliphatic tricarbamoyl having up to 24 carbon atoms isfor example a group ##STR16## with d being an integer from 2 to 6,preferably 6.

R₄ as aromatic tricarbamoyl having up to 24 carbon atoms is for examplebenzenetricarbamoyl.

R₄ as heterocyclic tricarbamoyl having up to 24 carbon atoms is forexample a group ##STR17## with e being an integer from 2 to 6,preferably 6.

R₄ as aliphatic C₆ -C₁₈ -tetraacyl may be C₄ -C₁₈ -alkanetetraoyl.Preferred examples are those tetraacyls derived from1,1,3,3-propanetetracarboxylic or 1,2,3,4-butanetetracarboxylic acids.

R₄ as aliphatic C₁₀ -C₁₈ -tetraacyl which is substituted with twonitrogen atoms is for example a group of the formula ##STR18##

A tetraacyl derived from ethylenediaminetetraacetic acid is preferred.

R₄ as aromatic C₁₀ -C₁₈ -tetraacyl is for example the tetraacyl derivedfrom 1,2,4,5-benzenetetracarboxylic acid.

R₄ as cycloaliphatic C₁₀ -C₂₂ -tetraacyl may be acycloalkanetetracarbonyl with 10 to 22 carbon atoms or acycloalkenetetracarbonyl with 10 to 22 carbon atoms. Examples are thefollowing groups: ##STR19##

Those compounds of formula (I) are preferred, in which R₁ is hydrogen,methyl, allyl, benzyl or acetyl, R₂ is hydrogen, C₁ -C₁₂ -alkyl, C₆ -C₉-cycloalkyl or C₆ -C₉ -aryl, R₃ is C₆ -C₁₂ -aryl or a group of theformula (II), n is 1, 2 or 3 and, if n is 1, R₄ is hydrogen, --COR₅,--COOR₆, --CO--R₇ --COOR₈, ##STR20## in which R₅ is hydrogen, C_(1`-C)₁₈ -alkyl, C₆ -C₉ -cycloalkyl, C₂ -C₄ -alkenyl, C₆ -C₈ -aryl, C₇ -C₁₆-aralkyl or C₁ -C₃ -alkyl substituted by a group of the formula (III)where W is --O-- or ##STR21## and R₁₅ is hydrogen, C₁ -C₁₂ -alkyl or C₆-C₉ -cycloalkyl, R₆ is C₁ -C₁₈ -alkyl, C₂ -C₆ -alkyl substituted by C₁-C₄ -alkoxy, C₆ -C₁₂ -cycloalkyl or a group of the formula (II), R₇ is adirect bond, C₁ -C₁₀ -alkylene, C₆ -C₈ -cycloalkylene, vinylene orphenylene, R₈ is hydrogen, C₁ -C₁₂ -alkyl, C₆ -C₉ -cycloalkyl, allyl ora group of the formula (II), R₉ and R₁₀, which are identical ordifferent, are hydrogen, C₁ -C₁₂ -alkyl, C₆ -C₉ -cycloalkyl, allyl or agroup of the formula (II), or, together with the nitrogen atom to whichthey are bonded, form part of a heterocyclic ring, R₁₁ is methyl, ethylor C₆ -C₉ -aryl, R₁₃ and R₁₄, which are identical or different, arehydrogen, C₁ -C₁₂ -alkyl, C₆ -C₉ -cycloalkyl, allyl or a group of theformula (II), X and Y, which are identical or different, are --O-- or##STR22## where R₁₆ is hydrogen, C₁ -C₁₂ -alkyl, OH-monosubstituted C₂-C₄ -alkyl, C₆ -C₉ -cycloalkyl, allyl or a group of the formula (II), orthe groups R₁₃ X-- and R₁₄ Y--, which are identical or different, are a1-pyrrolidinyl, 1-piperidyl, 4-morpholinyl or 1-hexahydroazepinyl groupor, if n is 2, R₄ is --CO--, ##STR23## in which R₁₇ is C₂ -C₁₂-alkylene, C₄ -C₁₂ -alkylene substituted in the chain by 1 or 2 oxygenatoms, C₆ -C₁₅ -cycloalkylene, 2-butene-1,4-diyl or a group of theformula (IV) in which R₂₃ is hydrogen or methyl, R₁₈ is a direct bond,C₁ -C₁₂ -alkylene, C₂ -C₁₂ -alkylidene, C₂ -C₈ -alkylene substituted inthe chain by one or two group where R₂₄ is C₁ -C₈ -alkyl, C₆ -C₉-cycloalkyl or a group of the formula (II), R₁₉ and R₂₁, which areidentical or different, are hydrogen, C₁ -C₈ -alkyl, C₆ -cycloalkyl or agroup of the formula (II), R₂₀ is C₂ -C₁₀ -alkylene, C₆ -C₁₅-cycloalkylene, C₆ -C₁₅ -arylene or xylylene, R₂₂ is hydrogen, C₁ -C₁₂-alkyl, OH-monosubstituted C₂ -C₄ -alkyl, C₆ -C₉ -cycloalkyl, allyl or agroup of the formula (II) and Z is --O-- or ##STR24## with R₁₆ asdefined above, or --ZR₂₂ is halogen, R₂₅ is C₁ -C₄ -alkyl and, if n is3, R₄ is aliphatic C₄ -C₈ -triacyl, a group N(CH₂ CO--)₃, aromatic orheterocyclic triacyl having up to 10 carbon atoms or a1,3,5-triazine-2,4,6-triyl group.

Those compounds of formula (I) are preferred, in which R₁ is hydrogen,methyl, allyl, benzyl or acetyl, R₂ is hydrogen, C₁ -C₁₂ -alkyl, C₆ -C₉-cycloalkyl or C₆ -C₉ -aryl, R₃ is C₆ -C₁₂ -aryl or a group of theformula (II), n is 1, 2 or 3 and, if n is 1, R₄ is hydrogen or one ofthe groups ##STR25## in which R₅ is hydrogen, C₁ -C₁₈ -alkyl, C₆ -C₉-cycloalkyl, C₂ -C₄ -alkenyl, C₆ -C₈ -aryl, C₇ -C₁₆ -aralkyl or C₁ -C₃-alkyl substituted by a group of the formula (III) where W is --O-- or##STR26## and R₁₅ is hydrogen, C₁ -C₁₂ -alkyl or C₆ -C₉ -cycloalkyl, R₆is C₁ -C₁₂ -alkyl, C₆ -C₁₂ -cycloalkyl or a group of the formula (II),R₇ is a direct bond, C₁ -C₈ -alkylene, C₆ -C₈ -cycloalkylene, vinyleneor phenylene, R₈ is C₁ -C₁₂ -alkyl, C₆ -C₉ -cycloalkyl, allyl or a groupof the formula (II), R₉ and R₁₀, which can be identical or different,are hydrogen, C₁ -C₁₂ -alkyl, C₆ -C₉ -cycloalkyl, allyl or a group ofthe formula (II), or, together with the nitrogen atom to which they arebonded, form part of a heterocyclic ring, such as pyrrolidine,piperidine, morpholine or hexahydroazepine, R₁₁ is methyl, ethyl or C₆-C₉ -aryl, R₁₃ and R₁₄, which can be identical or different, arehydrogen, C₁ -C₁₂ -alkyl, C₆ -C₉ -cycloalkyl, allyl or a group of theformula (II), X and Y, which can be identical or different, are --O-- or##STR27## where R₁₆ is hydrogen, C₁ -C₁₂ -alkyl, C₆ -C₉ -cycloalkyl,allyl or a group of the formula (II), or the groups R₁₃ X-- and R₁₄ Y--,which can be identical or different, are a 1-pyrrolidinyl, 1-piperidyl,4-morpholinyl or 1-hexahydroazepinyl group or, if n is 2, R₄ is a --CO--group or one of the groups ##STR28## in which R₁₇ is C₂ -C₁₀ -alkylene,C₆ -C₁₅ -cycloalkylene, 2-butene-1,4-diyl or a group of the formula (IV)in which R₂₃ is hydrogen or methyl, R₁₈ is a direct bond, C₁ -C₁₂-alkylene, C₂ -C₁₂ -alkylidene, C₂ -C₈ -alkylene substituted in thechain by one or two groups ##STR29## where R₂₄ is C₁ -C₈ -alkyl, C₆ -C₉-cycloalkyl or a group of the formula (II), R₁₉ and R₂₁, which can beidentical or different, are hydrogen, C₁ -C₈ -alkyl, C₆ -C₉ -cycloalkylor a group of the formula (II), R₂₀ is C₂ -C₁₀ -alkylene, C₆ -C₁₅-cycloalkylene, C₆ -C₁₅ -arylene or xylylene, R₂₂ is hydrogen, C₁ -C₁₂-alkyl, C₆ -C₉ -cycloalkyl, allyl or a group of the formula (II) and Zis --O-- or ##STR30## with R₁₆ as defined above, or, if n is 3, R₄aliphatic C₄ -C₈ -triacyl, a group N(CH₂ CO--)₃, aromatic orheterocyclic triacyl having up to 10 carbon atoms or a1,3,5-triazine-2,4,6-triyl group.

Those compounds of formula (I) are particularly preferred, in which R₁is hydrogen or methyl, R₂ is hydrogen or methyl, R₃ is2,2,6,6-tetramethyl-4-piperidyl or 1,2,2,6,6-pentamethyl-4-piperidyl, nis 1, 2 or 3 and, if n is 1, R₄ is hydrogen or one of the groups##STR31## in which R₅ is C₁ -C₁₇ -alkyl, cyclohexyl or phenyl, R₆ is C₂-C₁₈ -alkyl, C₆ -C₁₀ -cycloalkyl or a group of the formula (II) with R₁being hydrogen or methyl, R₈ is C₂ -C₁₂ -alkyl, cyclohexyl or a group ofthe formula (II) with R₁ being hydrogen or methyl, R₉ is hydrogen, R₁₀is C₄ -C₁₂ -alkyl or cyclohexyl, R₁₃ and R₁₄, which can be identical ordifferent, are C₁ -C₁₂ -alkyl, cyclohexyl, allyl or a group of theformula (II) with R₁ being hydrogen or methyl, and X and Y, which can beidentical or different, are a group ##STR32## where R₁₆ is hydrogen, C₁-C₁₂ -alkyl, cyclohexyl, allyl or a group of the formula (II) with R₁being hydrogen or methyl and, if n is 2, R₄ is one of the groups##STR33## in which R₁₇ is C₄ -C₁₀ -alkylene, C₆ -C₈ -cycloalkylene or agroup of the formula (IV) in which R₂₃ is hydrogen, R₁₈ is a directbond, C₁ -C₈ -alkylene, C₂ -C₈ -alkylidene, cyclohexylene or phenylene,R₁₉ and R₂₁ are hydrogen, R₂₀ is C₆ -C₉ -alkylene or C₆ -C₁₃ -arylene,R₂₂ is C₁ -C₁₂ -alkyl, cyclohexyl, allyl or a group of the formula (II)with R₁ being hydrogen or methyl, and Z is --O-- or ##STR34## with R₁₆being as defined above, and, if n is 3, R₄ is a1,3,5-triazine-2,4,6-triyl group.

R₁ is preferably hydrogen, C₁ -C₄ -alkyl, allyl, benzyl or acetyl, inparticular hydrogen or methyl.

Compounds of formula (I) wherein R₂ is hydrogen, C₁ -C₄ -alkyl,cyclohexyl, phenyl or benzyl and R₃ is phenyl unsubstituted orsubstituted by C₂ -C₄ -alkoxycarbonyl or is a group of the formula (II)are preferred.

Compounds of formula (I) wherein R₁ is hydrogen or methyl, R₂ ishydrogen or C₁ -C₄ -alkyl and R₃ is phenyl substituted by C₂ -C₄-alkoxycarbonyl or is a group of formula (II) are particularlypreferred.

Those compounds of formula (I) are of interest, wherein n is 1, 2 or 3and, if n═1, R₄ is hydrogen, CN, --COR₅, --COOR₆, --CO--R₇ --COOR₈,##STR35## in which R₅ is hydrogen, C₁ -C₁₈ -alkyl, cyclopentyl,cyclohexyl unsubstituted or substituted by C₁ -C₄ -alkyl, C₂ -C₁₈-alkenyl, phenyl unsubstituted or substituted by C₁ -C₄ -alkyl, by C₁-C₄ -alkoxy and/or by OH, C₇ -C₁₀ -phenylalkyl unsubstituted orsubstituted at the phenyl ring by C₁ -C₄ -alkyl and/or by OH, C₁ -C₁₀-alkyl substituted by C₁ -C₁₈ -alkoxy, by C₂ -C₁₈ -dialkylamino or by agroup of the formula (III) ##STR36## where R₁ is hydrogen, 0.sup.., CN,NO, cyanomethyl, C₁ -C₁₂ -alkyl, C₃ -C₁₂ -alkenyl or C₃ -C₁₂ -alkynylsubject to the proviso that the carbon atom attached to the nitrogenatom is a primary carbon atom, C₇ -C₁₂ -aralkyl, C₁ -C₁₂ -acyl,2,3-epoxypropyl, OH-monosubstituted C₂ -C₆ -alkyl or 2,3-dihydroxypropyland W is --O-- or ##STR37## where R₁₅ is hydrogen, C₁ -C₁₈ -alkyl,cyclopentyl, cyclohexyl unsubstituted or substituted by C₁ -C₄ -alkyl,C₃ -C₁₈ -alkenyl, phenyl unsubstituted or substituted by C₁ -C₄ -alkyl,by C₁ -C₄ -alkoxy and/or by OH, C₇ -C₁₀ -phenylalkyl unsubstituted orsubstituted at the phenyl ring by C₁ -C₄ -alkyl and/or by OH, or is agroup of the formula (II), R₆ is C₁ -C₁₈ -alkyl, C₂ -C₆ -alkylsubstituted by OH, by C₁ -C₁₈ -alkoxy or by C₂ -C₁₈ -dialkylamino,cyclopentyl, cyclohexyl unsubstituted or substituted by C₁ -C₄ -alkyl,or is C₃ -C₁₈ -alkenyl, phenyl unsubstituted or substituted by C₁ -C₄-alkyl and/or by C₁ -C₄ -alkoxy, C₇ -C₁₀ -phenylalkyl unsubstituted orsubstituted at the phenyl ring by C₁ -C₄ -alkyl and/or by OH, or is agroup of the formula (II), R₇ is a direct bond, C₁ -C₁₈ -alkylene,C.sub. 2 -C₂₀ -alkylidene, C₇ -C₂₀ -phenylalkylidene, cyclohexyleneunsubstituted or substituted by C₁ -C₄ -alkyl, C₂ -C₁₈ -alkenylene orphenylene, R₈ is as defined for R₆ or is hydrogen or an alkali metal, R₉and R₁₀, which are identical or different, are as defined for R₁₅, or R₉and R₁₀, together with the nitrogen atom to which they are bonded, forma pyrrolidine, piperidine, morpholine or hexahydroazepine group, R₁₁ isC₁ -C₁₂ -alkyl or phenyl unsubstituted or substituted by C₁ -C₃ -alkyland/or by C₁ -C₃ -alkoxy, R₁₃ and R₁₄, which are identical or different,are as defined for R₆ or are hydrogen, and X and Y, which are identicalor different, are a direct bond, --O-- or ##STR38## where R₁₆ is asdefined for R₁₅ or is OH-monosubstituted C₂ -C₆ -alkyl, or the groupsR₁₃ X-- and R₁₄ Y--, which are identical or different, are a1-pyrrolidinyl, 1-piperidyl, 4-morpholinyl, 1-hexahydroazepinyl or4-methyl-1-piperazinyl group, or, if n=2, R₄ is --CO--, --SO₂ --,--COO--R₁₇ --OOC--, --CO--R₁₈ --CO--, ##STR39## in which R₁₇ is C₂ -C₁₈-alkylene, C₄ -C₁₂ -alkylene substituted in the chain by 1 or 2 oxygenatoms, cyclohexylene, C₈ -C₁₈ -cyclohexylenedialkylene, C₁₃ -C₁₈-alkylenedicyclohexylene, C₁₄ -C₁₈ -alkylidenedicyclohexylene, C₄ -C₈-alkenylene, phenylene, xylylene or a group of the formula (IV)##STR40## where R₂₃ is hydrogen, C₁ -C₄ -alkyl or phenyl, R₁₈ is adirect bond, C₁ -C₁₈ -alkylene, C₂ -C₂₀ -alkylidene, C₇ -C₂₀-phenylalkylidene, cyclohexylene unsubstituted or substituted by C₁ -C₄-alkyl, phenylene, C₂ -C₁₂ -alkylene substituted in the chain by 1 or 2oxygen atoms or by 1 or 2 groups ##STR41## where R₂₄ is as defined forR₁₅, R₁₉ and R₂₁, which are identical or different, are as defined forR₁₅, R₂₀ is C₂ -C₁₈ -alkylene, cyclohexylene unsubstituted orsubstituted by C₁ -C₄ -alkyl, C₈ -C₁₈ -cyclohexylenedialkylene, C₁₃ -C₁₈-alkylenedicyclohexylene, phenylene, xylylene, R₂₂ is as defined for R₁₃and R₁₄, Z is as defined for X and Y, or --ZR₂₂ is 1-pyrrolidinyl,1-piperidyl, 4-morpholinyl, 1-hexahydroazepinyl or4-methyl-1-piperazinyl or halogen, R₂₅ is C₁ -C₄ -alkyl, or, if n =3, R₄is C₄ -C₁₈ -alkanetrioyl unsubstituted or substituted by OH, N(CH₂CO--)₃, benzenetricarbonyl or a group ##STR42## or isbenzenetricarbamoyl or a 1,3,5-triazine-2,4,6-triyl group, a .tbd.Pgroup, a .tbd.PO group or a group (--CO--R₇ --COO)₃ Al with R₇ asdefined above. n is preferably 1, 2 or 3, in particular 1 or 2.

Compounds of formula (I) wherein R₃ is a group of the formula (II) arepreferred.

If n is 1, R₄ is in particular --COR₅, --COOR₆ or ##STR43## and if n is2, R₄ is preferably --COO--R₁₇ --OOC--, --CO--R₁₈ --CO-- or ##STR44##

Those compounds of formula (I) are preferred, wherein n is 1, 2 or 3and, if n=1, R₄ is selected from the group consisting of hydrogen,##STR45## wherein R₅ is C₁ -C₁₈ -alkyl, R₆ is C₁ -C₁₈ -alkyl, C₂ -C₆-alkyl substituted by C₁ -C₄ -alkoxy, cyclohexyl unsubstituted orsubstituted by C₁ -C₄ -alkyl or is a group of the formula (II), R₇ is C₁-C₁₀ -alkylene, R₈ is hydrogen, R₉ and R₁₀ are independently hydrogen,C₁ -C₄ -alkyl or cyclohexyl, R₁₃ and R₁₄ are independently hydrogen, C₁-C₈ -alkyl, allyl or a group of formula (II), X and Y are independently--O-- or ##STR46## R₁₆ is hydrogen, C₁ -C₈ -alkyl, OH-monosubstituted C₂-C₄ -alkyl, allyl or a group of the formula (II),

if n=2, R₄ is selected from the group consisting of --COO--R₁₇ --OOC--,##STR47## wherein R₁₇ is C₂ -C₁₂ -alkylene or C₄ -C₁₂ -alkylenesubstituted in the chain by 1 or 2 oxygen atoms, R₁₈ is a direct bond orC₁ -C₁₀ -alkylene, R₁₉ and R₂₁ are hydrogen, R₂₀ is C₂ -C₁₀ -alkylene orcyclohexylene unsubstituted or substituted by C₁ -C₄ -alkyl, R₂₂ is C₁-C₈ -alkyl, OH-monosubstituted C₂ -C₄ -alkyl or allyl, Z is --O-- or##STR48## with R₁₆ being as defined above or

--ZR₂₂ is halogen, R₂₅ is C₁ -C₄ -alkyl and, if n=3, R₄ is1,3,5-triazine-2,4,6-triyl.

Those compounds of formula (I) are particularly preferred, wherein R₁ ishydrogen, R₂ is hydrogen or methyl, R₃ is2,2,6,6-tetramethyl-4-piperidyl, n is 1, 2 or 3 and, if n is 1, R₄ is--COR₅, --COOR₆ or ##STR49## in which R₅ is C₁ -C₁₈ -alkyl, R₆ is C₁-C₁₈ -alkyl, cyclohexyl, 4-t-butylcyclohexyl or1,2,2,6,6-pentamethyl-4-piperidyl, R₁₃ and R₁₄ are independently C₁ -C₈-alkyl or allyl, X and Y are independently --O-- or ##STR50## with R₁₆being hydrogen, C₁ -C₈ -alkyl, allyl or 2,2,6,6-tetramethyl-4-piperidyland, if n is 2, R₄ is --COO--R₁₇ --OOC--, --CO--R₁₈ --CO-- or ##STR51##in which R₁₇ is C₄ -C₆ -alkylene, R₁₈ is a direct bond or C₁ -C₈-alkylene, R₂₂ is C₁ -C₈ -alkyl or allyl and Z is --O-- or ##STR52##with R₁₆ being as defined above and, if n is 3, R₄ is a1,3,5-triazine-2,4,6-triyl group.

Those compounds of formula (I) are of interest, wherein R₁ is hydrogen,R₂ is hydrogen or methyl, R₃ is 2,2,6,6-tetramethyl-4-piperidyl, n is 1or 2 and, if n is 1, R₄ is --COOR₆ or ##STR53## in which R₆ is C₄ -C₁₈-alkyl, cyclohexyl, 4-t-butylcyclohexyl or1,2,2,6,6-pentamethyl-4-piperidyl, R₁₃ and R₁₄ are independently C₁ -C₄-alkyl, X and Y are ##STR54## with R₁₆ being2,2,6,6-tetramethyl-4-piperidyl, and, if n is 2, R₄ is --COO--R₁₇--OOC-- or ##STR55## in which R₁₇ is C₄ -C₆ -alkylene, R₂₂ is C₁ -C₄-alkyl or allyl and Z is --O-- or ##STR56## with R₁₆ being hydrogen, C₁-C₄ -alkyl or allyl.

Especially preferred examples of compounds of formula (I) are: ##STR57##

The compounds of the formula (I) may be obtained by two differentprocedures, depending on the nature of the group R₃, for example firstpreparing the compounds with n=1 and R₄ =H; from these, the compoundswith n=1, 2, 3 or 4 and R₄ ≠H may be prepared by reaction with suitableacylating agents.

If R₃ is a group of the formula (II), the corresponding compounds of theformula (I) can be prepared for example in accordance with scheme 1, byreacting 2 moles of a piperidylamine (V) with 1 mol of an orthoester(VI) in which R' is C₁ -C₄ -alkyl, the amidine (VII) being formed withelimination of the alcohol R'OH. The compounds of the formula (I) withR₃ being a group of the formula (II) and R₄ ≠H may be then obtained fromthe compounds of the formula (VII) by acylation. ##STR58##

If R₃ is C₆ -C₁₈ -aryl, the corresponding compounds of the formula (I)can be prepared for example in accordance with scheme 2, by reacting apiperidylamine (V) with an alkylimidate (VIII) in which R' is as definedabove, the amidine (IX) being formed with elimination of the alcoholR'OH.

The compounds of the formula (I) with R₃ =C_(6-C) ₁₈ -aryl and R₄ ≠H maybe then prepared from the compounds of the formula (IX) by acylation.##STR59##

The reactions a) in schemes 1 and 2 can be carried out for example withor without an inert solvent, operating at a temperature from 80° to 250°C., preferably from 100° to 180° C., with removal of the alcoholliberated in the reaction.

The ratio of the reagents is not critical, and it is possible to use anexcess of one or the other of the reagents.

The subsequent acylation reactions b) in schemes 1) and 2) can becarried out preferably in an inert solvent at a temperature from -20° to200° C., preferably from 0° to 180° C.; the reaction conditions dependon the type of acylating agent used.

If an acyl halide is used as the acylating agent, the hydrohalic acidliberated in the reaction is neutralized preferably with an inorganicbase, such as e.g. sodium or potassium hydroxide or carbonate, in aquantity at least equivalent to the acid liberated in the reaction. Thereactions according to schemes 1) and 2) can be carried out in a singlereactor without isolation of the amidine (VII) or (IX), but it is alsopossible to separate these compounds off and to employ them afterpurification in the subsequent acylation reactions.

In order to illustrate the present invention more clearly, severalexamples of the preparation of compounds of the formula (I) aredescribed below; these examples are given by way of illustration onlyand do not imply any restriction.

EXAMPLE 1

93.76 g (0.6 mol) of 2,2,6,6-tetramethyl-4-piperidylamine and 88.92 g(0.6 mol) of triethyl orthoformate are heated to 140°-150° C., withremoval of the ethanol liberated in the reaction.

Heating is continued until the evolution of ethanol ceases. Aftercooling, the precipitate formed is separated off by filtration, washedwith n-hexane and dried. This gives the compound of the formula##STR60## of melting point 175°-176° C.

Analysis for C₁₉ H₃₈ N₄.

Calculated: C 70.75%; H 11.87%; N 17.37%.

Found: C 70.78%; H 11.96%; N 17.32%.

EXAMPLES 2 and 3

Following the procedure of Example 1, and using the appropriatereagents, the following compounds of the general formula

    ______________________________________                                         ##STR61##                                                                    are prepared:                                                                                        Melting point                                          Example       R.sub.2  (°C.)                                           ______________________________________                                        2             CH.sub.3 93-94                                                  3             C.sub.2 H.sub.5                                                                        45-46                                                  ______________________________________                                    

EXAMPLE 4

To a suspension of 32.25 g (0.1 mol) ofN,N'-bis-(2,2,6,6-tetramethyl-4-piperidyl)-formamidine (prepared asdescribed in Example 1) in 150 ml of dichloromethane, cooled to 0° to+5° C., a solution of 11.39 g (0.105 mol) of ethyl chloroformate in 30ml of dichloromethane is added slowly, while not exceeding 10° C. Afterthe end of the addition, the mixture is stirred for 2 hours, allowingthe temperature to rise up to 20° C., and is then again cooled to about5° C., and a solution of 4.4 g (0.11 mol) of sodium hydroxide in 30 mlof water is slowly added, while not exceeding 10° C. After the end ofthe addition, stirring is continued for 2 hours, allowing thetemperature to rise up to 20° C.

The organic phase is separated off, washed with water, dried over Na₂SO₄ and evaporated to dryness.

The residue obtained is crystallized from ethyl acetate.

This gives the compound of the formula ##STR62## of melting point123°-124° C.

Analysis for C₂₂ H₄₂ N₄ O₂.

Calculated: C 66.96%; H 10.73%; N 14.20%.

Found: C 66.65%; H 10.71%; N 14.06%.

EXAMPLES 5-28

Following the procedure of Example 4, and using the appropriatereagents, the following compounds of the general formula

    __________________________________________________________________________     ##STR63##                                                                    are prepared:                                                                                                 Melting point                                 Example                                                                            n  R.sub.2                                                                            R.sub.4            °C.                                    __________________________________________________________________________     5   1  H    COOC.sub.4 H.sub.9 89-90                                          6   1  H                                                                                   ##STR64##         172-173                                        7   1  H    COC.sub.7 H.sub.15 oil                                            8   2  H    COO(CH.sub.2).sub.4OOC                                                                           172-173                                        9   2  H    CO(CH.sub.2).sub.8CO                                                                             148-149                                       10   1  CH.sub.3                                                                           COOC.sub.2 H.sub.5 oil                                           11   1  C.sub.5 H.sub.5                                                                    COOC.sub.2 H.sub.5 oil                                           12   1  CH.sub.3                                                                           COOC.sub.4 H.sub.9 92-94                                         13   1  H                                                                                   ##STR65##         157-158                                       14   2  H    COO(CH.sub.2).sub.6OOC                                                                           165-167                                       15   2  H    COCO               262-263                                       16   2  H    CO(CH.sub.2).sub.4CO                                                                             155-156                                       17   1  H    COC.sub.17 H.sub.35                                                                              wax                                           18   2  H    CO(CH.sub.2).sub.2 CO                                                                            238-240                                       19   1  H                                                                                   ##STR66##         125-126                                       20   1  H    COCH.sub.3         127-129                                       21   1  H                                                                                   ##STR67##         55-56                                         22   1  H    COOCH.sub.2 CH.sub.2 OCH.sub.3                                                                   94-95                                         23   2  H    COO(CH.sub.2).sub.2 O(CH.sub.2).sub.2 OOC                                                        140-141                                       24   2  H                                                                                   ##STR68##         162-163                                       25   1  H    COOC.sub.18 H.sub.37                                                                             69-70                                         26   1  H    COOC.sub.14 H.sub.29                                                                             55-56                                         27   1  H    COC.sub.11 H.sub.23                                                                              60-62                                         28   1  H    CO(CH.sub.2).sub.2 COOH                                                                          185-186                                       __________________________________________________________________________

EXAMPLE 29

64.5 g (0.2 mol) ofN,N'-bis-(2,2,6,6-tetramethyl-4-piperidyl)-formamidine are added slowlyto a solution of 18.45 g (0.1 mole) of cyanuric chloride in 500 ml ofxylene cooled to 10° C., maintaining the temperature between 10° and 15°C.

After the end of the addition, the mixture is heated for 2 hours at50°-55° C., 53 g (0.5 mol) of anhydrous ground Na₂ CO₃ are added, andthe mixture is heated for 3 hours at 70° C. and then filtered hot.

A white solid precipitates from the filtered solution, and this isseparated off by filtration and dried.

This gives the compound of the formula ##STR69## of melting point206°-207° C.

Analysis for C₄₁ H₇₄ Cl N₁₁.

Calculated: Cl=4.69%.

Found: Cl=4.71%.

EXAMPLE 30

158 g (0.49 mol) ofN,N'-bis-(2,2,6,6-tetramethyl-4-piperidyl)-formamidine are added slowlyto a solution of 27.7 g (0.15 mol) of cyanuric chloride in 300 ml oftrimethylbenzene, maintaining the temperature at 25°-30° C.

The mixture is then heated for one hour to 100°-110° C., 18.9 g ofpowdered sodium hydroxide are added, and heating is continued underreflux for 12 hours with azeotropic removal of the water of reaction.

The mixture is diluted with 100 ml of trimethylbenzene, cooled andfiltered.

The residue obtained after dryness is washed with water and then withmethyl ethyl ketone, and then dried again.

This gives the compound of the formula ##STR70## of melting point295°-296° C.

Analysis for C₆₀ H₁₁₁ N₁₅.

Calculated: C 69.12%; H 10.73%; N 20.15%.

Found: C 68.77%; H 10.72%; N 20.01%.

EXAMPLES 31-43

Following the procedure of Example 30, and using the appropriatereagents, the following compounds of the general formula

    __________________________________________________________________________     ##STR71##                                                                    are prepared:                                                                                                        Melting point                          Example                                                                            A                    B            °C.                             __________________________________________________________________________    31                                                                                  ##STR72##                                                                                          ##STR73##   224-225                                32                                                                                  ##STR74##                                                                                          ##STR75##   176-177                                33                                                                                  ##STR76##           C.sub.4 H.sub.9 O                                                                          236-237                                34                                                                                  ##STR77##           (C.sub.2 H.sub.5).sub.2N                                                                   232-234                                35                                                                                  ##STR78##           NHCH.sub.2 CHCH.sub.2                                                                      246-248                                36   N(CH.sub.2 CHCH.sub.2).sub.2                                                                       N(CH.sub.2 CHCH.sub.2).sub.2                                                               198-200                                37   NHCH.sub.2 CHCH.sub.2                                                                              NHCH.sub.2 CHCH.sub.2                                                                      159-160                                38                                                                                  ##STR79##           OC.sub.3 H.sub.7 iso                                                                       226-227                                39                                                                                  ##STR80##           N(CH.sub.3).sub.2                                                                          205-206                                40                                                                                  ##STR81##           N(C.sub.4 H.sub.9).sub.2                                                                   199-200                                41                                                                                  ##STR82##           N(CH.sub.2 CHCH.sub.2).sub.2                                                               215-216                                42                                                                                  ##STR83##           N(CH.sub.2 CH.sub.2 OH).sub.2                                                              210-212                                43   N(C.sub.2 H.sub.5).sub.2                                                                           N(C.sub.2 H.sub.5).sub.2                                                                   121-122                                __________________________________________________________________________

EXAMPLE 44

165.2 g (1 mol) of ethyl 4-aminobenzoate and 296.4 g (2 mol) of triethylorthoformate are heated for 2 hours at 110° C., separating off theethanol liberated in the reaction. The excess triethyl orthoformate isremoved by heating to 110° C. in vacuo (24 mbar). The mixture is cooled,diluted with 600 ml of n-hexane, heated under reflux for 30 minutes andthen allowed to cool, and the solid which has separated out is filteredoff, washed with 300 ml of hexane and dried.

55.3 g (0.25 mol) of ethyl (4-ethoxycarbonylphenyl)-formimidate thusobtained and 39 g (0.25 mol) of 2,2,6,6-tetramethyl-4-piperidylamine areheated for 6 hours at 100° C. After cooling, 200 ml of acetone are addedand the mixture is filtered.

The product obtained is washed with acetone and dried.

This gives a compound of the formula ##STR84## of melting point110°-111° C.

Analysis for C₁₉ H₂₉ N₃ O₂.

Calculated: C 68.85%; H 8.82%; N 12.68%.

Found: C 68.89%; H 8.90; N 12.80%.

EXAMPLE 45

A solution of 8.58 g (0.051 mol) of hexamethylene diisocyanate in 20 mlof toluene is added slowly to 33.15 g (0.1 mol) ofN-(2,2,6,6-tetramethyl-4-piperidyl)-N'-(4-ethoxycarbonylphenyl)formamidine(prepared as described in Example 44), dissolved in 100 ml of toluene.The mixture is then heated for 4 hours at 80° C. and evaporated todryness under reduced pressure (26.7 mbar). The solid obtained iscrystallized from acetone.

This gives the compound of the formula ##STR85## of melting point151°-152° C.

Analysis for C₄₆ H₇₀ N₈ O₆.

Calculated: C 69.15%; H 7.81%; N 12.40%.

Found: C 69.01%; H 7.86%; N 12.28%.

EXAMPLES 46-48

Following the procedure of Example 45, and using the appropriatereagents, the following compounds are prepared:

    __________________________________________________________________________                                                        Melting                                                                       point                     Ex.                                                                              Formula                                          °C.                __________________________________________________________________________    46                                                                                ##STR86##                                       172-173                   47                                                                                ##STR87##                                       199-200                   48                                                                                ##STR88##                                       168-169                   __________________________________________________________________________

EXAMPLE 49

To a suspension of 32.25 g (0.1 mol) ofN,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-formamidine (prepared asdescribed in Example 1) in 150 ml of dichloromethane, cooled to 0° to 5°C., a solution of 14.24 g (0.105 mol) of diethyl carbamoylchloride in 30ml of dichloromethane is added slowly while not exceeding 10° C.

After addition, the mixture is stirred, heating under reflux for 8hours.

Then the mixture is cooled to about 5° C. and a solution of 4.4 g (0.11mol) of sodium hydroxide in 30 ml of water is slowly added, while notexceeding 10° C.

After addition, stirring is continued for 1 hour, allowing thetemperature to rise up to 20° C.

The organic phase is separated off, washed with water and dried over Na₂SO₄. The solvent is evaporated and the residue obtained is crystallizedfrom n-hexane.

This gives the compound of the formula ##STR89## of melting point90°-91° C.

Analysis for C₂₄ H₄₇ N₅₀.

Calculated: C 68.36%; H 11.23%; N 16.61%.

Found: C 68.01%; H 11.20%; N 16.33%.

EXAMPLE 50

To a suspension of 80.60 g (0.25 mol) ofN,N'-bis-(2,2,6,6-tetramethyl-4-piperidyl)-formamidine (prepared asdescribed in Example 1) in 600 ml of dichloromethane, cooled to 0° to 5°C., a solution of 43.10 g (0.25 mol) of diethylchlorophosphate in 100 mlof dichloromethane is added slowly, while not exceeding 10° C. Afteraddition the mixture is stirred for 2 hours allowing the temperature torise up to 20° C., and then it is cooled again to about 5° C.

A solution of 10.8 g (0.27 mol) of sodium hydroxide in 100 ml of wateris slowly added, while not exceeding 10° C.

After addition, stirring is continued for 2 hours, allowing thetemperature to rise up to 20° C.

The organic phase is separated off, washed with water, dried over Na₂SO₄ and evaporated to dryness.

The residue obtained is crystallized from octane.

This gives the compound of the formula ##STR90## of melting point104°-106° C.

Analysis for C₂₃ H₄₇ N₄ O₃ P monohydrate.

Calculated: C 57.7%; H 10.4%; N 11.7%.

Found: C 57.37%; H 10.37%; N 11.6%.

EXAMPLE 51

Following the procedure of Example 4, and using the appropriatereagents, the compound of the formula ##STR91##

As mentioned at the outset, the compounds of the formula (I) are veryeffective in improving the light stability, heat stability and oxidationstability of organic materials, preferably synthetic polymers, inparticular polyolefins.

Examples of organic materials which can be stabilized with compounds offormula (I) are:

Polymers of monoolefins and diolefins, for example polyethylene (whichmay be crosslinked), polypropylene, polyisobutylene, poly-1-butene,polymethyl-1-pentene, polyisoprene or polybutadiene, and also polymersof cycloolefins, for example of cyclopentene or norbornene. Mixtures ofthe said polymers, for example mixtures of polypropylene withpolyisobutylene.

Copolymers of monoolefins and diolefins with one another or with othervinyl monomers, for example ethylene/propylene, propylene/1-butene,propylene/isobutylene, ethylene/1-butene, propylene/butadiene,isobutylene-isoprene, ethylene/vinyl acetate. ethylene/alkyl acrylates,ethylene/alkyl methacrylates or ethylene/acrylic acid copolymers andtheir salts (ionomers) and terpolymers of ethylene with propylene and adiene such as hexadiene, dicyclopentadiene or ethylidenenorbornene.

Polystyrene and poly-(p-methylstyrene).

Copolymers of styrene or α-methylstyrene with dienes or acrylicderivatives, for example styrene/butadiene, styrene/acrylonitrile,styrene/ethyl methacrylate, styrene/butadiene/ethyl acrylate,styrene/acrylonitrile/methyl acrylate, high-impact strength mixtures ofstyrene copolymers and other polymers, for example a polyacrylate, adiene polymer or an ethylene/propylene/diene terpolymer, and blockcopolymers of styrene, for example styrene/butadiene/styrene,styrene/isoprene/styrene, styrene/ethylene/butylene/styrene orstyrene/ethylene/propylene/styrene.

Graft copolymers of styrene, for example styrene on polybutadiene,styrene and acrylonitrile on polybutadiene, styrene and alkyl acrylatesor methacrylates on polybutadiene, styrene and acrylonitrile onethylene/propylene/diene terpolymers, styrene and acrylonitrile onpolyacrylates or polymethacrylates, styrene and acrylonitrile onacrylate/butadiene copolymers, and also mixtures with the copolymersmentioned under the preceding heading, for example the mixtures known asABS, MBS, ASA or AES polymers.

Halogen-containing polymers, such as polychloroprene, chlorinatedrubbers, chlorinated or sulfochlorinated polyethylene, polymers andcopolymers of epichlorohydrin, polymers of halogen-containing vinylcompounds, for example polyvinyl chloride, polyvinylidene chloride,polyvinyl fluoride and polyvinylidene fluoride, and also copolymersthereof, for example vinyl chloride/vinylidene chloride, vinylchloride/vinyl acetate or vinylidene chloride/vinyl acetate copolymers.

Polymers derived from α,β-unsaturated acids and their derivatives, suchas polyacrylates and polymethacrylates, polyacrylamides andpolyacrylonitrile.

Copolymers of the monomers under the preceding heading, mixed with oneanother or with other unsaturated monomers, for exampleacrylonitrile/butadiene, acrylonitrile/alkyl acrylate,acrylo-nitrile/alkoxyalkyl acrylate or acrylonitrile/vinyl halidecopolymers or acrylonitrile/alkyl methacrylate/butadiene terpolymers.

Polymers derived from unsaturated alcohols and amines or their acyl oracetal derivatives, such as polyvinyl alcohol, polyvinyl acetate,polyvinyl stearate, polyvinyl benzoate, polyvinyl maleate, polyvinylbutyral, polyallyl phthalate or polyallylmelamine.

Homopolymers and copolymers of cyclic ethers, such as polyalkyleneglycols, polyethylene oxide, polypropylene oxide or their copolymerswith bis-glycidyl ethers.

Polyacetals, such as polyoxymethylene and the polyoxymethylenescontaining ethylene oxide as a comonomer.

Polyphenylene oxides and sulfides, and mixtures of polyphenylene oxideswith polystyrene.

Polyurethanes derived on the one hand from polyethers, polyesters orpolybutadiene with hydroxyl end groups and, on the other hand, aliphaticor aromatic polyisocyanates, and also their precursors (polyisocyanates,polyols or prepolymers). Polyamides and copolyamides derived fromdiamines and dicarboxylic acids and/or aminocarboxylic acids or thecorresponding lactams, such as nylon-4, nylon-6, nylon-6/6 nylon-6/10,nylon-11, nylon-12, poly-2,4,4-trimethylhexamethylene-terephthalamide orpoly-m-phenylene-isophthalamide, and also their copolymers withpolyethers, for example with polyethylene glycols, polypropylene glycolsor polytetramethylene glycols.

Polyureas, polyimides and polyamide-imides.

Polyesters derived from dicarboxylic acids and diols and/orhydroxycarboxylic acids or corresponding lactones, such as polyethyleneterephthalate, polybutylene terephthalate,poly-1,4-dimethylolcyclohexane terephthalate,poly-2,2-(4-hydroxyphenyl)-propane terephthalate andpolyhydroxybenzoate, and also the block copolyetheresters derived frompolyethers with hydroxyl end groups.

Polycarbonates and polyester-carbonates.

Polysulfones, polyether-sulfones and polyether-ketones.

Crosslinked polymers derived from aldehydes on the one hand and phenols,ureas and melamines on the other hand, such as phenol/formaldehyderesins, urea/formaldehyde resins and melamine/formaldehyde resins.

Drying and non-drying alkyd resins.

Unsaturated polyester resins derived from copolyesters of saturated andunsaturated dicarboxylic acids with polyalcohols and vinyl compounds ascrosslinking agents, and also their halogen-containing modifications oflow inflammability.

Thermosetting acrylic resins derived from substituted acrylic esters,such as epoxy-acrylates, urethane-acrylates and polyesteracrylates.

Alkyd resins, polyester resins or acrylate resins mixed with melamineresins, urea resins, polyisocyanates or epoxide resins as crosslinkingagents.

Crosslinked epoxide resins derived from polyepoxides, for example frombis-glycidyl ethers or cycloaliphatic diepoxides.

Natural polymers of the type of cellulose, rubber, gelatine and theirderivatives with chemical polymer-homologous modifications, such ascellulose acetates, cellulose propionates and cellulose butyrates, orcellulose ethers such as methylcellulose.

Mixtures of the above polymers, for example PP/EPDM, nylon-6/EPDM orABS, PVC/EVA, PVC/ABS, PVC/MBS, PC/ABS and PBTP/ABS.

The compounds of formula (I) are in particular useful in stabilizingpolyethylen and polypropylen.

The compounds of the formula (I) can be mixed with the organic materialin various proportions depending on the nature of the polymer, on theend use and on the presence of other additives.

In general, it is advantageous to employ from 0.01 to 5% by weight ofthe compounds of the formula (I), relative to the weight of the organicmaterial, preferably from 0.05 to 1%.

The compounds of the formula (I) can be incorporated into the polymericmaterials via various processes, such as dry blending in the form ofpowders, or wet mixing in the form of solutions or suspensions, ormixing in the form of a master-batch; in these operations, the polymercan be employed in the form of powder, granules, a solution, asuspension or in the form of a latex.

The polymers stabilized with the products of the formula (I) can be usedfor the preparation of moulded articles, films, tapes, fibres,monofilaments, surface-coatings and the like.

If desired, the stabilized compositions of this invention may optionallyalso contain for example from about 0.05 to about 5%, preferably fromabout 0.1 to about 2.5% by weight of various conventional additives,such as antioxidants, UV absorbers, nickel stabilizers, pigments,fillers, plasticizers, antistatic agents, flameproofing agents,lubricants, anti-corrosion agents, metal deactivators and others.

Examples of additives which can be mixed with the compounds of theformula (I) are in particular:

Antioxidants belonging to the following classes:

Alkylated monophenols, for example:

2,6-Di-t-butyl-4-methylphenol, 2-t-butyl-4,6-dimethylphenol,2,6-di-t-butyl-4-ethylphenol, 2,6-di-t-butyl-4-n-butylphenol,2,6-di-t-butyl-4-i-butylphenol, 2,6-di-cyclopentyl-4-methylphenol,2-(α-methylcyclohexyl)-4,6-dimethylphenol,2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexylphenol and2,6-di-t-butyl-4-methoxymethylphenol.

Alkylated hydroquinones, for example:

2,6-Di-t-butyl-4-methoxyphenol, 2,5-di-t-butylhydroquinone,2,5-di-t-amylhydroquinone and 2,6-diphenyl-4-octadecyloxyphenol.

Thiobisphenols, for example:

2,2'-Thio-bis-(6t-butyl-4-methylphenol), 2,2'-thio-bis-(4-octylphenol),4,4'-thio-bis-(6-t-butyl-3-methylphenol) and4,4'-thio-bis(6-t-butyl-2-methylphenol).

Alkylidene-bisphenols, for example:

2,2'-Methylene-bis-(6-t-butyl-4-methylphenol),2,2'-methylene-bis(6-t-butyl-4-ethylphenol),2,2'-methylene-bis-[4-methyl-6-(α-methylcyclohexyl)-phenol],2,2'-methylene-bis-(4-methyl-6-cyclohexylphenol),2,2'-methylene-bis-(6-nonyl-4-methylphenol),2,2'-methylene-bis-[6-(α-methylbenzyl)-4-nonylphenol],2,2'-methylene-bis-[6-(α,α-dimethylbenzyl)-4-nonylphenol],2,2'-methylene-bis-(4,6-di-t-butylphenol),2,2'-ethylidene-bis-(4,6-di-t-butylphenol),2,2'-ethylidene-bis-(6-t-butyl-4-isobutylphenol),4,4'-methylene-bis(2,6-di-t-butylphenol),4,4'-methylene-bis-(6-t-butyl-2-methylphenol),1,1-bis-(5-t-butyl-4-hydroxy-2-methylphenyl)-butane,2,6-bis-(3-t-butyl-5-methyl-2-hydroxybenzyl)-4-methylpenol,1,1,3-tris-(5-t-butyl-4-hydroxy-2-methylphenyl)-butane,1,1-bis-(5-t-butyl-4-hydroxy-2-methylphenyl)-3-n-dodecylmercaptobutane,ethylene glycol bis-[3,3-bis-(3'-t-butyl-4'-hydroxyphenyl-butyrate],bis-(3-t-butyl-4-hydroxy-5-methylphenyl)-dicyclopentadiene andbis-[2-(3'-t-butyl-2'-hydroxy-5'-methylbenzyl)-6-t-butyl-4-methylphenyl]-terephthalate.

Benzyl compounds, for example:

1,3,5-Tris-(3,5-di-t-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene,bis-(3,5-di-t-butyl-4-hydroxybenzyl)sulfide, isooctyl3,5-di-t-butyl-4-hydroxybenzyl-mercaptoacetate,bis-(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) dithiolterephthalate,1,3,5-tris-(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate,1,3,5-tris-(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate,dioctadecyl 3,5-di-t-butyl-4-hydroxybenzyl-phosphonate and calciummonoethyl 3,5-di-t-butyl-4-hydroxybenzyl-phosphonate.

Acylaminophenols, for example:

Lauric acid 4-hydroxyanilide, stearic acid 4-hydroxyanilide,2,4-bis-(octylmercapto)-6-(3,5-t-butyl-4-hydroxyanilino)-s-triazine andoctyl N-(3,5-di-t-butyl-4-hydroxyphenyl)-carbamate.

Esters of β-(3,5-di-t-butyl-4-hydroxyphenyl)-propionic acid withmonohydric or polyhydric alcohols, for example:

methanol, octadecanol, 1,6-hexanediol, neopentyl glycol, thiodiethyleneglycol, diethylene glycol, triethylene glycol, pentaerythritol,tris-(hydroxyethyl)-isocyanurate and N,N'-bis-(hydroxyethyl)-oxamide.

Esters of β-(5-t-butyl-4-hydroxy-3-methylphenyl)-propionic acid withmonohydric or polyhydric alcohols, for example: methanol, octadecanol,1,6-hexanediol, neopentyl glycol, thiodiethylene glycol, diethyleneglycol, triethylene glycol, pentaerythritol,tris-(hydroxyethyl)-isocyanurate and N,N'-bis-(hydroxyethyl)-oxamide.

Amides of β-(3,5-di-t-butyl-4-hydroxyphenyl)-propionic acid:N,N'-Bis-(3,5-di-t-butyl-4-hydroxyphenylpropionyl)-hexamethylenediamine,N,N'-bis-(3,5-di-t-butyl-4-hydroxyphenylpropionyl)-trimethylenediamineand N,N'-bis-(3,5-di-t-butyl-4-hydroxyphenyl-propionyl)-hydrazine.

UV absorbers and light stabilizers belonging to the following groups:

2-(2'-Hydroxyphenyl)-benzotriazoles, for example the 5'-methyl,3',5'-di-t-butyl, 5'-t-butyl, 5'-(1,1,3,3-tetramethylbutyl),5-chloro-3',5'-di-t-butyl, 5-chloro-3'-t-butyl-5'-methyl,3'-sec.-butyl-5'-t-butyl, 4'-octoxy-3',5'-di-t-amyl and3',5'-bis-(α,α-dimethylbenzyl) derivatives.

2-Hydroxybenzophenones, for example the 4-hydroxy, 4-methoxy, 4-octoxy,4-decyloxy, 4-dodecyloxy, 4-benzyloxy, 4,2',4'-trihydroxy and2'-hydroxy-4,4'-dimethoxy derivatives.

Esters of various substituted benzoic acids, for example: phenylsalicylate, 4-t-butylphenyl salicylate, octylphenyl salicylate,dibenzoylresorcinol, bis-(4-t-butylbenzoyl)-resorcinol,benzoylresorcinol, 2,4-di-t-butylphenyl3,5-di-t-butyl-4-hydroxybenzoate, hexadecyl3,5-di-t-butyl-4-hydroxybenzoate andN-ethyl-N-phenyl-N'-(p-ethoxycarbonylphenyl)-formamidine.

Acrylates, for example ethyl or isooctyl α-cyano-β,β-diphenylacrylate,methyl α-carbomethoxycinnamate, methyl or butylα-cyano-β-methyl-p-methoxycinnamate, methylα-carbomethoxy-p-methoxycinnamate andN-(β-carbomethoxy-β-cyanovinyl)-2-methylindoline.

Nickel compounds, for example nickel complexes of2,2'-thio-bis-[4-(1,1,3,3-tetramethylbutyl)-phenol], such as the 1:1 or1:2 complexes, which may contain additional ligands such asn-butylamine, triethanolamine or N-cyclohexyl-diethanolamine, nickeldibutyldithiocarbamate, nickel salts of the monoalkyl esters of4-hydroxy-3,5-di-t-butylbenzylphosphonic acid, such as the methyl, ethylor butyl esters, nickel complexes of ketoximes such as2-hydroxy-4-methylphenyl undecyl ketoxime and nickel complexes of1-phenyl-4-lauroyl-5-hydroxypyrazole with or without additional ligands.

Sterically hindered amines, for examplebis-(2,2,6,6-tetramethylpiperidyl) sebacate,bis-(1,2,2,6,6-pentamethylpiperidyl) sebacate,bis-(1,2,2,6,6-pentamethylpiperidyl)n-butyl-3,5-di-t-butyl-4-hydroxybenzylmalonate, the condensation productof 1-(hydroxyethyl)-2,2,6,6-tetramethyl-4-hydroxypiperidine and succinicacid, the condensation product ofN,N'-bis-(2,2,6,6-tetramethylpiperidyl)-hexamethylenediamine and4-t-octylamino-2,6-dichloro-1,3,5-triazine,tris-(2,2,6,6-teramethylpiperidyl) nitrilotriacetate,tetrakis(2,2,6,6-tetramethylpiperidyl) 1,2,3,4-butanetetracarboxylateand 1,1'-(1,2-ethanediyl)-bis-(3,3,5,5-tetramethylpiperazinone).

Oxalic acid diamides, for example 4,4'-dioctyloxy-oxanilide,2,2'-dioctyloxy-5,5'-di-t-butyloxanilide,2,2'-didodecyloxy-5,5'-di-t-butyloxanilide, 2-ethoxy-2'-ethyloxanilide,N,N'-bis-(3-dimethylaminopropyl)-oxalamide,2-ethoxy-5-t-butyl-2'-ethyloxanilide and its mixtures with2-ethoxy-2'-ethyl-5,4'-di-t-butyloxanilide, and mixtures of ortho-andpara-methoxy- and also o- and p-ethoxy-disubstituted oxanilides.

Metal deactivators, for example N,N'-diphenyloxamide,N-salicylal-N'-salicyloylhydrazine, N,N'-bis-(salicyloyl)-hydrazine,N,N'-bis-(3,5-di-t-butyl-4-hydroxyphenylpropionyl)-hydrazine,3-salicyloylamino-1,2,4-triazole and bis-(benzylidene)-oxalodihydrazide.

Phosphites and phosphonites, for example triphenyl phosphite, diphenylalkyl phosphites, phenyl dialkyl phosphites, tris-(nonylphenyl)phosphite, trilauryl phosphite, trioctadecyl phosphite, distearylpentaerythritol diphosphite, tris-(2,4-di-t-butylphenyl) phosphite,diisodecyl pentaerythritol diphosphite, di-(2,4-di-t-butylphenyl)pentaerythritol diphosphite, tristearyl sorbitol diphosphite andtetrakis-(2,4-di-t-butylphenyl) 4,4'-diphenylene-diphosphonite.

Peroxide-destroying compounds, for example esters of β-thiodipropionicacid, for example the lauryl, stearyl, myristyl or tridecyl esters,mercaptobenzimidazole or the zinc salt of 2-mercaptobenzimidazole, zincdibutyl-dithiocarbamate, dioctadecyl disulfide and pentaerythritoltetrakis-(β-dodecyl-mercapto)propionate.

Polyamide stabilizers, for example copper salts in combination withiodides and/or phosphorus compounds and divalent manganese salts.

Basic costabilizers, for example melamine, polyvinylpyrrolidone,dicyandiamide, triallyl cyanurate, urea derivatives, hydrazinederivatives, amines, polyamides, polyurethanes, alkali metal or alkalineearth metal salts of higher fatty acids, for example calcium stearate,zinc stearate, magnesium stearate, sodium ricinoleate and potassiumpalmitate, antimony pyrocatecholate or zinc pyrocatecholate.

Nucleating agents, for example 4-t-butylbenzoic acid, adipic acid anddiphenylacetic acid.

Fillers and reinforcing agents, for example calcium carbonate,silicates, glass fibres, asbestos, talc, kaolin, mica, barium sulfate,metal oxides and hydroxides, carbon black and graphite.

Further additives, for example plasticizers, lubricants, emulsifiers,pigments, fluorescent brighteners, flameproofing agents, antistaticagents and foaming agents.

The efficiency, as stabilizers, of the products prepared according tothe invention, is illustrated in the examples which follow, in whichsome products obtained in the preparation examples are used forstabilizing polypropylene plates and tapes.

Example 52: 1 g of each of the compounds indicated in Table 1, 0.5 g oftris-(2,4-di-t-butylphenyl) phosphite, 0.5 g of pentaerythritoltetrakis-[3-(3,5-di-t-butyl-4-hydroxyphenyl) -propionate], 1 g of BluePhthalocyanine, 1 g of calcium stearate and 1,000 g of polypropylenepowder (melt index=2.4 g/10 min; measured at 230° C. and 2,16 kp) areintimately mixed in a slow mixer. The mixtures obtained are extruded ata temperature of 200°-220° C. to give polymer granules which are thenconverted into plaques of 2 mm thickness by injection-moulding at190°-220° C.

The plaques obtained are exposed in a model 65 WR Weather-O-Meter (ASTMG26-77) at a black panel temperature of 63° C. until the start ofsuperficial embrittlement (chalking).

For comparison, a polypropylene plaque prepared under the sameconditions as indicated above, but without the addition of the compoundsof the invention, is exposed.

Table 1 shows the exposure time (in hours) required to reach the startof superficial embrittlement.

                  TABLE 1                                                         ______________________________________                                        Stabilizer       Embrittlement time (hours)                                   ______________________________________                                        Without stabilizer                                                                               500                                                        Compound of Example 4                                                                          4,300                                                        Compound of Example 5                                                                          4,800                                                        Compound of Example 6                                                                          4,000                                                        Compound of Example 8                                                                          3,600                                                        Compound of Example 13                                                                         3,800                                                        Compound of Example 21                                                                         3,750                                                        Compound of Example 49                                                                         3,900                                                        ______________________________________                                    

Example 53: 1 g of each of the compounds indicated in Table 2, 0.5 g oftris-(2,4-di-t-butylphenyl) phosphite, 0.5 g of pentaerythritoltetrakis-[3-(3,5-di-t-butyl-4-hydroxyphenyl)-propionate] and 1 g ofcalcium stearate are mixed in a slow mixer with 1,000 g of polypropylenepowder (melt index=3 g/10 min; measured at 230° C. and 2.16 kp).

The mixtures obtained are extruded at a temperature of 200°-220° C. togive polymer granules which are then converted into stretched tapes of50 μm thickness and 2.5 mm width, using a semitechnical-scale apparatus(Leonard, Sumisago (VA)-Italy), under the following working conditions:

Extruder temperature: 220°-240° C.:

Head temperature: 260° C.:

Stretch ratio: 1:6.

The tapes thus prepared are exposed, mounted on a white card, in a model65 WR Weather-O-Meter (ASTM G26-77), with a black panel temperature of63° C.

The residual tenacity is measured on samples, taken after various timesof exposure to light, by means of a constant-speed tensometer; theexposure time in hours (T₅₀) needed to halve the initial tenacity isthen calculated.

For comparison, tapes prepared under the same conditions as indicatedabove, but without the addition of the compounds of the invention, areexposed. The results obtained are shown in Table 2.

                  TABLE 2                                                         ______________________________________                                        Stabilizer         T.sub.50 (hours)                                           ______________________________________                                        Without stabilizer   190                                                      Compound of Example 10                                                                           2,710                                                      Compound of Example 13                                                                           2,150                                                      Compound of Example 14                                                                           2,500                                                      Compound of Example 18                                                                           2,200                                                      Compound of Example 20                                                                           2,100                                                      Compound of Example 21                                                                           2,400                                                      Compound of Example 33                                                                           2,800                                                      Compound of Example 34                                                                           3,150                                                      Compound of Example 46                                                                           2,450                                                      Compound of Example 49                                                                           2,300                                                      ______________________________________                                    

What is claimed is:
 1. A compound of formula I ##STR92## in which R₁ ishydrogen, O° , CN, NO, cyanomethyl, C₁ -C₁₂ -alkyl, C₃ -C₁₂ -alkenyl orC₃ -C₁₂ -alkynyl subject to the proviso that the carbon atom attached tothe nitrogen atom is a primary carbon atom, C₇ -C₁₂ -aralkyl, C₁ -C₁₂-alkanoyl, C₃ -C₁₂ -alkenoyl, C₃ -C₁₂ -alkynoyl, benzoyl or benzoylsubstituted by one or more of C₁ -C₄ -alkyl or -OH; 2,3-epoxypropyl,OH-monosubstituted C₂ -C₆ -alkyl or 2,3-dihydroxypropyl, R₂ is hydrogen,C₁ -C₁₈ -alkyl, C₅ -C₁₈ -cycloalkyl, C₆ -C₁₈ -aryl or C₇ -C₁₈ -aralkyl,R₃ is C₆ -C₁₈ -aryl or a group of the formula (II) ##STR93## in which R₁is as defined above, n is an integer from 1 to 4, when n=1, R₄ isselected from the group consisting of hydrogen, CN, ##STR94## in whichR₅ is hydrogen, C₁ -C₁₈ -alkyl, C₅ -C₁₈ -cycloalkyl, C₂ -C₁₈ -alkenyl,C₆ -C₁₈ -aryl, C₇ -C₁₈ -aralkyl or C₁ -C₁₀ -alkyl substituted by C₁ -C₁₈-alkoxy, by C₂ -C₁₈ -dialkylamino or by a group of the formula (III)##STR95## where R₁ is as defined above and W is --O-- or ##STR96## whereR₁₅ is hydrogen, C₁ -C₁₈ -alkyl, C₅ -C₁₈ -cycloalkyl, C₃ -C₁₈ -alkenyl,C₆ -C₁₈ -aryl, C₇ -C₁₈ -aralkyl or a group of the formula (II), R₆ is C₁-C₁₈ -alkyl, C₂ -C₆ -alkyl substituted by OH, by C₁ -C₁₈ -alkoxy or byC₂ -C₁₈ -dialkylamino, C₅ -C₁₈ -cycloakyl, C₃ -C₁₈ -alkenyl, C₆ -C₁₈-aryl, C₇ -C₁₈ -aralkyl or a group of the formula (II), R₇ is a directbond, C₁ -C₁₈ -alkylene, C₂ -C₂₀ -alkylidene, C₇ -C₂₀ -aralkylidene, C₆-C₁₀ -cycloalkylene, C₂ -C₁₈ -alkenylene or C₆ -C₁₀ -arylene, R₈ is asdefined for R₆ or is hydrogen or an alkali metal, R₉ and R₁₀, which areidentical or different, are as defined for R₁₅, or R₉ and R₁₀, togetherwith the nitrogen atom to which they are bonded, form part of a5-membered to 7-membered heterocyclic ring, which is 1-pyrrolidinyl,1-piperidyl, 4-morpholinyl, 1-hexahydroazepinyl or4-methyl-1-piperazinyl, R₁₁ is C₁ -C₁₂ -alkyl or C₆ -C₁₂ aryl, r is 0 or1, R₁₂ is C₁ -C₁₂ -alkyl or a group of the formula II, or the two groupsR₁₂ together are C₂ -C₁₂ -alkylene or C₆ -C₂₈ -arylene and together withthe phosphorus atom and the two oxygen atoms form a 5-membered to7-membered ring selected from the group consisting of ##STR97## whenn=2, R₄ is selected from the group consisting of --CO--, --SO₂ --,--COO--R₁₇ --OOC--, --COCOO--R₁₇ --OOCCO--, --CO--R₁₈ --CO--, ##STR98##in which R₁₇ is C₂ -C₁₈ -alkylene, C₄ -C₁₂ -alkylene substituted in thechain by 1 or 2 oxygen atoms, C₆ -C₁₈ -cycloalkylene, C₄ -C₈-alkenylene, C₆ -C₁₈ -arylene, C₈ -C₁₂ -aralkylene or a group of theformula (IV) ##STR99## where R₂₃ is hydrogen, C₁ -C₄ -alkyl or phenyl,R₁₈ is a direct bond, C₁ -C₁₈ -alkylene, C₂ -C₂₀ -alkylidene, C₇ -C₂₀-aralkylidene, C₆ -C₁₀ -cycloalkylene, C₆ -C₁₀ -arylene, C₂ -C₁₂-alkylene substituted in the chain by 1 or 2 oxygen atoms or by 1 or 2groups ##STR100## where R₂₄ is as defined for R₁₅, R₁₉ and R₂₁, whichare identical or different, are as defined for R₁₅, R₂₀ is C₂ -C₁₈-alkylene, C₆ -C₁₈ -cycloalkylene, C₆ -C₁₈ -arylene or C₈ -C₁₂-aralkylene, R₂₅ is C₁ -C₄ -alkyl, s is 0 or 1, R₇ is as definedhereinabove and M is Ba, Ca, Co", Mg, Mn", Ni", Sn" or Zn,when n=3, R₄is selected from the group consisting of aliphatic C₄ -C₁₈ -triacyl,aliphatic C₆ -C₁₈ -triacyl substituted by a nitrogen atom, aromatic orheterocyclic triacyl having up to 18 carbon atoms, substitutedaliphatic, aromatic or heterocyclic tricarbomyl having up to 24 carbonatoms, a .tbd.P group, a .tbd.PO group and a group (--CO--R₇ --COO)₃ Alwith R₇ as defined hereinabove, when n=4 R₄ is selected from the groupconsisting of aliphatic C₆ -C₁₈ -tetraacyl, aliphatic C₁₀ -C₁₈-tetraacyl substituted by two nitrogen atoms, aromatic C₁₀ -C₁₈-tetraacyl, cycloaliphatic C₁₀ -C₂₂ -tetraacyl and a group (--CO--R₇--COO)₄ Sn^(IV), where R₇ is as defined hereinabove, with the provisothat, when R₃ is aryl of 6 to 18 carbon atoms, R₄ is not hydrogen.
 2. Acompound according to claim 1, in which R₁ is hydrogen, methyl, allyl,benzyl or acetyl, R₂ is hydrogen, C₁ -C₁₂ -alkyl, C₆ -C₉ -cycloalkyl orC₆ -C₉ -aryl, R₃ is C₆ -C₁₂ -aryl or a group of the formula (II), n is1, 2 or 3 and, when n is 1, R₄ is hydrogen or one of the groups##STR101## in which R₅ is hydrogen, C₁ -C₁₈ -alkyl, C₆ -C₉ -cycloalkyl,C₂ -C₄ -alkenyl, C₆ -C₈ -aryl, C₇ -C₁₆ -aralkyl or C₁ -C₃ -alkylsubstituted by a group of the formula (III) where W is --O-- or##STR102## and R₁₅ is hydrogen, C₁ -C₁₂ -alkyl or C₆ -C₉ -cycloalkyl, R₆is C₁ -C₁₂ -alkyl, C₆ -C₁₂ -cycloalkyl or a group of the formula (II),R₇ is a direct bond, C₁ -C₈ -alkylene, C₆ -C₈ -cycloalkylene, vinyleneor phenylene, R₈ is C₁ -C₁₂ -alkyl, C₆ -C₉ -cycloalkyl, allyl or a groupof the formula (II), R₉ and R₁₀, which are identical or different, arehydrogen, C₁ -C₁₂ -alkyl, C₆ -C₉ -cycloalkyl, allyl or a group of theformula (II), or, together with the nitrogen atom to which they arebonded form part of a heterocyclic ring, R₁₁ is methyl, ethyl or C₆ -C₉-aryl, or, when n is 2, R₄ is a --CO-- group or one of the groups##STR103## in which R₁₇ is C₂ -C₁₀ -alkylene, C₆ -C₁₅ -cycloalkylene,2-butene-1,4-diyl or a group of the formula (IV) in which R₂₃ ishydrogen or methyl, R₁₈ is a direct bond, C₁ -C₁₂ -alkylene, C₂ -C₁₂-alkylidene, C₂ -C₈ -alkylene substituted in the chain by one or twogroups ##STR104## where R₂₄ is C₁ -C₈ -alkyl, C₆ -C₉ -cycloalkyl or agroup of the formula (II), R₁₉ and R₂₁, which are identical ordifferent, are hydrogen, C₁ -C₈ -alkyl, C₆ -C₉ -cycloalkyl or a group ofthe formula (II), R₂₀ is C₂ -C₁₀ -alkylene, C₆ -C₁₅ -cycloalkylene, C₆-C₁₅ -arylene or xylylene, or, when n is 3, R₄ is aliphatic C₄ -C₈-triacyl, a group N(CH₂ CO--)₃, aromatic or heterocyclic triacyl havingup to 10 carbon atoms.
 3. A compound according to claim 11, in which R₁is hydrogen or methyl, R₂ is hydrogen or methyl, R₃ is2,2,6,6-tetramethyl-4-piperidyl or 1,2,2,6,6-pentamethyl-4-piperidyl, nis 1, or 2 and, when n is 1, R₄ is hydrogen or one of the groups##STR105## in which R₅ is C₁ -C₁₇ -alkyl, cyclohexyl or phenyl, R₆ is C₂-C₁₈ -alkyl, C₆ -C₁₀ -cycloalkyl or a group of the formula (II) with R₁being hydrogen or methyl, R₈ is C₂ -C₁₂ -alkyl, cyclohexyl or a group ofthe formula (II) with R₁ being hydrogen or methyl, R₉ is hydrogen, R₁₀is C₄ -C₁₂ -alkyl or cyclohexyl, and when n is 2, R₄ is one of thegroups ##STR106## in which R₁₇ is C₄ -C₁₀ -alkylene, C₆ -C₈-cycloalkylene or a group of the formula (IV) in which R₂₃ is hydrogen,R₁₈ is a direct bond, C₁ -C₈ -alkylene, C₂ -C₈ -alkylidene,cyclohexylene or phenylene, R₁₉ and R₂₁ are hydrogen, and R₂₀ is C₆ -C₉-alkylene or C₆ -C₁₃ -arylene,
 4. A compound according to claim 1wherein R₁ is hydrogen, C₁ -C₄ -alkyl, allyl, benzyl or acetyl.
 5. Acompound according to claim 1 wherein R₂ is hydrogen, C₁ -C₄ -alkyl,cyclohexyl, phenyl or benzyl and R₃ is phenyl unsubstituted orsubstituted by C₂ -C₄ -alkoxycarbonyl or is a group of the formula (II)in which R₁ is as defined in claim
 1. 6. A compound according to claim 1wherein R₁ is hydrogen or methyl, R₂ is hydrogen or C₁ -C₄ -alkyl and R₃is phenyl substituted by C₂ -C₄ -alkoxycarbonyl or is a group of formula(II) in which R₁ is as defined hereinabove.
 7. A compound according toclaim 1 wherein n is 1 or
 2. 8. A compound according to claim 1 whereinn is 1 and R₄ is --COR₅ or --COOR₆.
 9. A compound according to claim 1wherein n is 2 and R₄ is --COO--R₁₇ --OOC-- or --CO--R₁₈ --CO--.
 10. Acompound according to claim 1 wherein n is 1, or 2 and when n=1, R₄ isselected from the group consisting of hydrogen, ##STR107## wherein R₅ isC₁ -C₁₈ -alkyl, R₆ is C₁ -C₁₈ -alkyl, C₂ -C₆ -alkyl substituted by C₁-C₄ -alkoxy, cyclohexyl unsubstituted or substituted by C₁ -C₄ -alkyl oris a group of the formula (II) wherein R₁ is as defined in claim 1, R₇is C₁ -C₁₀ -alkylene, R₈ is hydrogen, R₉ and R₁₀ are independentlyhydrogen, C₁ -C₄ -alkyl or cyclohexyl,when n=2, R₄ is selected from thegroup consisting of --COO--R₁₇ --OOC--, ##STR108## wherein R₁₇ is C₂-C₁₂ -alkylene or C₄ -C₁₂ -alkylene substituted in the chain by 1 or 2oxygen atoms, R₁₈ is a direct bond or C₁ -C₁₀ -alkylene, R₁₉ and R₂₁ arehydrogen, R₂₀ is C₂ -C₁₀ -alkylene or cyclohexylene unsubstituted orsubstituted by C₁ -C₄ -alkyl, and R₂₅ is C₁ -C₄ -alkyl.
 11. A compoundaccording to claim 1 wherein R₁ is hydrogen, R₂ is hydrogen or methyl,R₃ is 2,2,6,6-tetramethyl-4-piperidyl, n is 1 or 2 and, when n is 1, R₄is --COR₅, or COOR₆ in which R₅ is C₁ -C₁₈ -alkyl, R₆ is C₁ -C₁₈ -alkyl,cyclohexyl, 4-t-butylcyclohexyl or 1,2,2,6,6-pentamethyl-4-piperidyl,and, when n is 2, R₄ is --COO--R₁₇ --OOC-- or --CO--R₁₈ --CO-- in whichR₁₇ is C₄ -C₆ alkylene, R₁₈ is a direct bond or C₁ -C₈ -.
 12. A compoundaccording to claim 1, in which R₁ is hydrogen, R₂ is hydrogen or methyl,R₃ is 2,2,6,6-tetramethyl-4-piperidyl, n is 1 or 2 and, when n is 1, R₄is --COOR₆ in which R₆ is C₄ -C₁₈ -alkyl, cyclohexyl,4-t-butylcyclohexyl or 1,2,2,6,6-pentamethyl-4-piperidyl, and, when n is2, R₄ is --COO--R₁₇ --OOC-- in which R₁₇ is C₄ -C₆ -alkylene.
 13. Thecompound ##STR109## according to claim 1.